Magic moments, the stuff we work for. I’ve been lucky enough to share a few over the journey so far. This magic moment occurred on a November day back in 2006. Myself and Rhian Clear (Frysie) had been conducting snorkelling surveys of the Cotter River to the west of Canberra looking for larvae and juvenile Macquarie perch. So far we had recorded a number of these in the first few pools immediately upstream of the Cotter Reservoir, which is a known strong hold of this endangered species. The pools immediately upstream of the reservoir were thought to be be important spawning locations by the presence of early juveniles observed snorkelling by Brendan Ebner & his team in 2001/2002. That year a fishway was installed some 6km upstream of the reservoir to provide Macquarie perch access to a further20-odd kilometres of stream in the hope that they would surmount the previously impassable road crossing and establish in the river upstream. Initial surveys failed to detect the presence of Macquarie perch above the fishway, despite all measurements and design characteristics suggesting that the fishway would be passable. Some years went by until a few observations of Macquarie perch upstream of the fishway started to trickle in, mostly by anglers, but one by a researcher in Brendan’s new team, a bloke who puts the “i” in team, literally (Jason Thiem). Spurred on by this, Brendan and myself set about designing a robust snorkelling technique to survey the river from the reservoir to a few kilometres upstream of the fishway to determine if indeed Macquarie perch had used the fishway to gain access to the river upstream to breed. Anyway, I digress (I’ve noticed a few of us on the Lair have digressive tendencies), on a nice November afternoon myself and Rhian were in the 3rd last pool of the day, when I noticed a very small larval fish. I promptly scooped up the little fish and placed it in a jar of river water. It didn’t have a forked tail, so that ruled out any of the likely exotics, leaving only Macquarie perch and Two-spined blackfish (common throughout the river). Somewhat buoyed by the prospect of discovering larval Macquarie perch several kilometres upstream of the fishway, we retained the specimen for further examination back at the lab (which was ultimately inconclusive).

Our next fortnightly snorkelling trip couldn’t come soon enough. In the second pool upstream of the fish way (some 1.5 km upstream), we hit the jackpot. Not one miserly little indiscriminate larval fish, but hordes of early juvenile Macquarie perch! There they were, buzzing about, predating upon microinverts, darting to and from cover in and out of the flow in the headwaters of each pool. In some pools, large schools of larvae hung in the water column hugging steep rock faces, moving deeper upon approach. They had done it! These placid, patient, beautiful native fish had pushed though the fishway, well up river and got their jiggy on! I’m pretty sure I even got a high-five out of Frysie that day, one of very few ever given as he is not keen on unnecessary physical contact. That day we recorded larvae or early juvenile Macquarie perch in 11 of the 13 pools we snorkelled upstream of the fishway (spanning 3.5 km). Certainly a research highlight, one that I’ll never forget!

Since that day, regular sampling by fyke nets and backpack electro-fishing have detected several age classes of Macquarie perch present in the river upstream of the fishway indicating that this population had colonised this newly accessible part of the range that had been taken from them. This success has also resulted in the fishway being repaired by flood damage on two occasions and another fishway being built further up the catchment.

Now you may think (like I did when I first arrived in the science world) that fish and pumps would not mix. A pump is affectively a giant blender and a fish (if it was unlucky enough to be sucked up) would not exit the pump in any form resembling a living fish. How wrong I was.

One of the lovely places I get to call my office on occasion is the Hattah Lakes system, part of the Hattah-Kulkyne National Park in north-western Victoria. It is comprised of around 18 lakes (12 of which are RAMSAR listed) nestled among the sand dunes. Chalka Creek feeds these lakes from the Murray River, but only during elevated flows.

Murray River with the entrance to Chalka Creek on the left

During the millennium drought flows in the Murray River were too low to flood into Chalka Creek. Consequently the lakes became dry and the once majestic River Red Gums bordering the water courses of this system were looking a little worse for wear. This resulted in management authorities deciding to pump environmental water from the Murray River into Chalka Creek and the lakes from 2005.

The Hattah Lakes were pumped numerous times over the next 5 years with the intention of keeping these trees alive and maintaining the ‘ecological character’ of the area. We, at the Murray–Darling Freshwater Research Centre (MDFRC), have undertaken monitoring work at these lakes since 2005, and this has included fish surveys.

Following pumping of environmental water from the Murray River into the bone dry Hattah Lakes, a diverse native fish community developed. The lakes were allowed to dry naturally (sadly resulting in the whole fish community perishing; there was no link back to the Murray River) and subsequent additions of environmental water led to the emergence of a similar fish community suggesting that the first time occurrence had not just been a chance event.

Temporary pump setup at Hattah on the Murray River (2010).

Notice that in the last paragraph I specified ‘native’ fish community? The community was indeed almost completely comprised of native species. Eastern gambusia, renowned for invading just about any pool of water, was not found in the Hattah Lakes following these pumping events. Also the number of Carp during this period appeared to be limited to only a handful which became apparent as the lake had dried to a small, shallow pool. Therefore we concluded that the pumps were somehow ‘filtering’ the fish community, though it was unclear if this was due to timing, depth, distance of abstraction pipe from bank, type of pump or any number of other factors.

In the summer of 2010–11, flooding in the Murray River caused Hattah Lakes to fill naturally for the first time in 10 years. As a result we found Spangled perch, which is as far south as had ever been recorded (see Iain ‘Listy’ Ellis spiel on Spangs) and Oriental weatherloach (which was previously recorded only as far west as Euston; ≈100km upstream). In the years following, fish catch in the Hattah Lakes were dominated by Carp and Eastern gambusia, proving that these species were more than happy to hang out in the Hattah Lakes once free access was granted.

Around the time of the flood, approval was granted to undertake the installation of a number of block banks and regulators around Hattah and the mother of all pumping stations (think 1000 ML.day-1) on the Murray River enabling artificial flooding of vast, long-dry, areas of the floodplain. Construction was completed last year and after the first pumping event took place some interesting fish results surfaced. However we will save that story for another time (and storyteller).

As I have only been at MDFRC for 5 years, after some quick math you might realise I was not on the scene during the initial pumping during the drought. This little piece would not have been possible without the hard work and slogging though much mud of the girls and guys that collected fish data from the Hattah Lakes in the years gone by. Also to the science nerds whom cottoned onto the fact that very few exotic species inhabited the lakes following pumping.

About 3 years ago I received the privilege of being asked to co-supervise my first Honours student. At first I wondered if I had enough knowledge and experience to be of any assistance as a co-supervisor because I had only graduated a couple of years earlier myself. Nevertheless, I tentatively agreed to take up the opportunity to co-supervise the student, Trevor, and so began 9 months of steep personal growth for both of us.

Trevor’s project investigated the diel, vertical and lateral migration patterns of microinvertebrates in the Broken River. The project involved undertaking a multitude of roles and tasks, ranging from working as a colleague alongside Trevor in numerous white-boarding sessions, being his lackey whilst sampling mosquito-infested backwaters in the pitch black of night, mentoring him in identifying microinvertebrates and undertaking multivariate analyses, and acting as a reviewer for his literature review and thesis.

I can’t deny in admitting that the workload associated with being a co-supervisor for the first time often felt a bit overwhelming when combined with the tasks and deadlines associated with my own project responsibilities, but the sheer number of rewarding moments derived from being a co-supervisor always outweighed any of the challenges. For example, there was the time when I got to see Trevor’s sense of relief and accomplishment when he finally submitted his thesis for examination, and the time that I saw him completely full of joy and pride when he graduated.

However, the most rewarding aspect of all was getting to watch Trevor grow during the 9 month period from being a relatively quiet and tentative student to a much more confident student that was now completely capable of undertaking his own research and thinking for himself. I learnt a lot of things during that first experience as a co-supervisor. Most of all I learnt about how rewarding it is to help mentor someone through the highs and lows of an Honours year and to know that you may have contributed to their personal growth in some small way.

Nathan Ning, by his own admission is only part fisho , other parts aquatic ecologist, and is beyond being labelled.

I was finished writing my first spiel about Spangled perch for the Lair, when I noticed the category of ‘Magic moments’. I reckon I’ve had a few of them. My first up close with a monster Murray cod for instance– that was magical. Standing on the front of an e-boat as what looked like a fridge emerged slowly from the turbid depths in front of me, before rolling to take the form of a huge fish – yep, magic. I’m not claiming it as “magic” in a hero kind of way – anybody who knows me knows I can’t angle for goldfish, let alone big natives. But geez that was an experience. Forty-four kilograms and 1.24 m of sweet native fish magic. And the crowning glory? …. the gentle flick of her massive tail as I held her briefly in the flow to recover before release.

I’m pretty sure I saw her again too ….three years later– in that same stream. It was the middle of a drought. Shallow, clear water – you could see the bottom. I was again standing on the front of a boat (why not when you have an office called the Murray-Darling Basin), drifting slowly downstream to a field site. Out she popped from under a snag to my left, gently gliding in front of us for a good ten metres. She surged, winked (I swear!), to then disappear beneath a mass of logs and shadows. It still baffles me that some people keep them to mount above the fireplace.

Humphries, P. (2005). Spawning time and early life history of Murray cod, Maccullochella peelii peelii (Mitchell) in an Australian river. Environmental Biology of Fishes72, 393–407.

Koehn, J.D, and Harrington, D.J. (2005). Collection and distribution of the early life stages of the Murray cod (Maccullochella peelii peelii) in a regulated river. Australian Journal of Zoology53, 137–144.

Rowland, S.J. (1989). Aspects of the history and fishery of the Murray cod, Maccullochella peelii (Mitchell)(Percichthyidae). Proceedings of the Linnaean Society of New South Wales111, 201–213.

Editorial note: It is with some reluctance that I allow the following ramble to permeate on the Lair.

A few words on Eb and The moray’s lair

I like this webpage, and I hope it builds. I really do. I just spent an hour reminiscing as I typed, and that’s something I reckon we could all do more of. Too often we get wrapped up in the argey bargey of scientific competition, taking for granted the “friendships we made during our scientific endeavours” as Eb himself eloquently said, ‘It’s been really nice sharing some experiences without having to attach a p-value and some internationally relevant citations’ [to a piece of writing].

For those of you who don’t know Eb, he’s the bloke that started this Moray’s Lair thing. He’s also a guy you don’t want to share a tent with in 40° heat (manstink alert!). He’s the one who you don’t want to share a tent with on a chilly winter night either, when he’s fast asleep and dreaming of cuddling a warm body. He’s the one who knows everything (according to him)… but “nothing” according to his lovely and sharp -witted wife Louise.

Listy with the last of the Lake Hawthorn hardies (Murray hardyhead). These threatened fish were rescued months before their home dried up, and later released (successfully) to establish a translocated population – one of only four that remain in Victoria.

You’ll probably see him one day if you attend fishy conferences or workshops. He’s that guy talking everyone’s ear off at tea and lunch breaks, before doubling back to bite again during question time – after every presentation! You could introduce yourself, but he’ll probably beat you to it to be honest. On reflection Eb is a valuable asset to the fishos of Oz…. and by association, the fish they work on. He’s that special type of person that is the social glue binding fisho-goober-nerds together. We need folk like that to regularly breach the walls that our professional loyalties and alliances may create, and to knee-cap the ego’s that often fester behind those walls. This web page is an example of what I mean – most of us are too busy or perhaps selfish to even think of an idea like themorayslair.

When I think about it, he is also a bit of a mentor to me. He taught me how to sample for fish, introduced me to that Murray hardyhead fish I mentioned in my “species spotlight”, and he programmed me to hide my packing lists from colleagues, lest they form the basis of a really unnecessary nick-name. Eb essentially got me hooked on this freshwater fish thing I now call a job. Thank you for the opportunity Eb, it’s been fun.

In early May I caught a ~40 cm alien Rainbow trout (Oncorhynchus mykiss) in the Cotter River between Bendora Dam and Cotter Dam (in the Australian Capital Territory). I cleaned it and inspected its stomach contents … and discovered this trout had killed a 5 cm SL native Two-spined blackfish (Gadopsis bispinosus) earlier that day. Being in a gloomy section of river late in the day, I scrambled up a nearby scree slope to catch the late afternoon sun and illuminate this sad scene for a photo.

I have had the privilege of seeing Two-spined blackfish in the wild and in aquaria, and they are beautiful, charismatic little native fish with a lot of personality. I was deeply saddened to see one of these beautiful native fish ending its days in the gullet of a tawdry, extremely over-rated and unnecessary feral import … and promptly wondered how often this happens, unrecorded.

It’s not the first time. Over the years, I have recovered about seven Two-spined blackfish (~5 cm to 11.5 cm SL) and several juvenile Macquarie perch (~5 cm SL) from the gullets of Rainbow trout in the Cotter River system. Most of these observations (but not all) were made in the mid to late 1990s when I fished the Cotter River very frequently. It’s worth noting that I (foolishly) released most of my trout back then — had I kept them all, imagine how many more instances of trout predation I may have found! I also never happened to have a camera on me.

I am strongly critical of the impacts of alien trout — and in some cases, ongoing irresponsible stockings of alien trout — on upland native fish as well as other upland fauna such as the Spotted tree frog (Litoria spenceri), the Giant alpine stonefly (Thaumatoperla alpina) and spiny crayfish species of the genus Euastacus. I am of the considered opinion that the impacts of alien trout in Australia have been vastly underestimated. Historical evidence (e.g. Trueman, 2007, 2011), circumstantial and biological evidence (Cadwallader, 1996; Lintermans, 2000; Gilligan, 2005) are very substantial and very thought-provoking. But it is the parallels with terrestrial Australian wildlife — which have indisputably been devastated by alien terrestrial predators (e.g. Woinarski et al., 2014) — that really highlight the inherent absurdity of the all-too-often repeated claim that alien trout species, and decades of irresponsible saturation stockings of alien trout species, have had little or no impact on upland native fish and upland native fauna (e.g. NSW Fisheries, 2003; see also Halverson, 2011). And certainly alien trout impacts in Australia have been almost wholly unstudied. Ironically, with less and less upland native fish populations (particularly Murray-Darling Macquarie perch) surviving, opportunities for such studies become ever fewer.

I now carry a camera every time I go trout fishing, to photographically record examples of alien trout predation on native fish. This is my first photographic record.

My burning passion is the Maccullochella cod species, but I have a penchant for percichthyids, and native fish generally. I managed to never become a fish ecologist, despite strenuous effort and study. Instead, I wander the Commonwealth environment department like a displaced percichthyid and contribute to good policy outcomes, big and small, for native fish. I am a passionate fisherman, strictly catch-and-release with native fish, and love keeping native fish in aquaria too. Curious facts: I had a (tiny) meteorite burn up a few metres above my head one fine night; my favourite meal is the hearty French dish cassoulet.

The peacefulness of a river bank, somewhere, anywhere, interrupted by an exclamation “You little (insert appropriate expletive here)”, followed by rustling in the leaf litter and a ‘plop’ as a researcher struggles to find an escapee before throwing back (or releasing it un-ceremonially) an uncooperative fish – unwilling to lie nicely on the measurement board. Our experiences of measuring fish might suggest that native species have an ability to ‘jump’, however, documented observations are few and far between.

Sitting on the edge of a fishway one evening in southwestern Australia – a few good mates helping out, setting nets to catch upstream migrating juvenile stages of the Spotted trout minnow (Galaxias truttaceus) – one says, “a fish just climbed that weir”. Disbelieving, we all peered closer – thinking to ourselves…fishway….weir….climbing fish..??? Sure enough, we observed numerous fish, shunning the vertical slot fishway and successfully ascending the vertical weir wall (see Fig. 1a). During their ascent, fish maintained connection with the weir wall and used a modified swimming technique or ‘wriggle’ movement. Some fish were also observed to ‘rest’, mid ascent, maintaining a stationary position on the vertical weir wall. Approximately 30-40% of these climbers successfully reached a narrow angled skirt below the metal v-notch baffle (Fig. 1b). Up to 30 fish were observed congregated to the side of the flow and were exposed to the air, presumably for periods of minutes, but were kept moist with regular ‘water splash’. The fact that these individuals were capable of tolerating presumably short periods of exposure to air is interesting, although not unique in the Galaxiidae, which includes species capable of both long-term (e.g. aestivation) and short term exposure. From here, some fish successfully ascended the metal baffle using the same ‘climbing’ technique described above, however, did so with sufficient burst speed to achieve significant separation from the baffle and water surface (i.e. ‘jump’) and re-enter the water in the weir pool approximately 20cm upstream from the metal baffle. Prior to reaching the weir wall, these fish also negotiated turbulent and high velocity water created by the weir skirt (Fig 1a).

The ability of this species to ‘climb’ the vertical weir wall and to ‘jump’ contrasts with most other Australian native species and particularly their juvenile stages; less than 5% of approximately 205 native Australian freshwater species are thought to posses some ability to climb and jump. While the relative swimming ability of some large-bodied Australian freshwater species and their life stages have been documented, similar published information is generally lacking for the majority of small-bodied Australian native freshwater fish species. Further consideration of the climbing and jumping capabilities is required for freshwater migratory species to improve our ability to prioritise mitigation works on instream barriers and help improve fishway design.

These observations were made as part of a broader study on the threatened freshwater fish of south-western Australia, funded by the Western Australian Government’s State Natural Resource Management Program and carried out in collaboration with David Morgan and Stephen Beatty (Freshwater Fish Group and Fish Health Unit, Murdoch University) Tom Ryan (Centre of Excellence In Natural Resource Management, The University of Western Australia) and Craig Lawrence (Western Australian Fisheries and Marine Research Laboratories). This work has been recently published in the Australian Journal of Zoology (DOI: ZO14004).

Paul is from Fish Ecology Research and Monitoring in the Centre of Excellence in Natural Resource Management, University of Western Australia, Albany.

I don’t remember the title of the book. I was pretty young – maybe 4 years old. It was a children’s book, and it depicted Archimedes leaping out of the bathtub, shouting ‘EUREKA!’ at the top of his voice, followed by a nudie run down the street.

Fast forward 20-something years and I am at the Australian National University, doing my PhD research under the supervision of Chris Fulton and Brendan Ebner. Im working on the impossibly small otoliths of larval Eastern rainbowfish and Purple-spotted gudgeons.

During my PhD candidature I had two ‘Eureka’ moments. Multiple theoretical issues bugged me for weeks and months, swirling in my head but not quite forming a lucid picture I could put to paper. However, I quickly learnt that my subconscious works on these problems at night when I sleep. This article is about those moments.

Twice I woke up around 4am in the morning, with the answer clear in my mind. I didn’t go to bed thinking about the problem, but subconsciously, I had been working on it for months.

The first idea didn’t go anywhere. I raced into uni at 5am in the morning and wrote it all down. It’s still somewhere in a word document on my computer. Untouched. I can’t recall what it was about, but I have no inclination to dig it up.

The second moment I remember clearly. I had been struggling for months, trying to place my Purple-spotted gudgeon growth experiment (Starrs et al. 2013) into a broader framework – what is the significance of rapid growth in larvae, and how can that be put in the context of selective mortality? I knew there had to be a way to put these together, but I couldn’t figure it out in a way that made sense to me. Other people had done it, but not in the way I was thinking it should be done. Growth is a physiological process, and a population model should be built on the underlying physiology, not some surrogate halfway between.

Then, early one morning it hit me. I woke up, and it was right there. I had it! Using the same analytical framework I had studied in my Bachelor of Economics degree, I could combine the natural variation in growth response to temperature and food supply into a graphical model that could partition mortality, and reveal the proportion of any population that will experience selective pressure due to changes in their thermal environment, food supply and intrinsic physiology. For the next week, I crafted this idea. I think it works!

It currently sits on my computer, unfinished. A little bit of empirical data and some more modelling and it might be worth a neat little paper. Since then, similar ideas have appeared in the literature (Johnson et al. 2014). However, regardless of whether I revisit it or not, it still remains my ‘Eureka!’ (I didn’t do the nudie run).

‘Fish? In the desert?’ The most common response to the news that for the last three years, my PhD research has indeed centred on an unlikely candidate: the desert goby (Chlamydogobius eremius). In some ways, this species is the most unassuming member of the community of freshwater fishes found in the Lake Eyre Basin of arid Australia. In others, it is the most remarkable. And both my answer to that original query and my thinking on the science of what I do – exploring how an animal interacts with a changing environment via behaviour, genetics, and ecology – continues to be shaped by a series of small revelations. In fact, this is an experience probably reflective of why most scientists do what we do: to find out things.

Some of those discoveries happen in the form of small moments that drive inspiration and optimism: both particularly important given the many challenges to the conservation of biodiversity and natural systems. One such moment – tiny, but significant – happened after three years of staring at gobies in tanks, analysing hours of footage to explore mating behaviour, and tramping around desert waterholes and springs in search of this little fish. During night fishing, where slumbering gobies make for easy and gently caught targets, the endless mosquitoes have a field day with the unweathered flesh of distracted biologists. But, wading slowly through thigh deep water, my bare foot nudges a larger-than-usual rock; it wobbles lethargically, obviously uneven. We’re after adults tonight – the best candidates for a current experiment – but something tells me this is worth a detour. The water is cold, and there’s a hum of excitement from the mozzies at the rolling up of sleeves, but it barely registers. The mud is silky cold as I sink my fingers under the rocks edges, and then it’s free. I’m anticipating an expanse of mud-covered underside and nothing more, but there, nestled in a cozy crevice, is a bundle of treasures. A clutch of wild goby eggs, mid-way through their development thanks to the careful attention of the parental male, who will attentively guard the eggs from would-be predators and fans them continually to maintain the flow of oxygenated water. While desert gobies are relatively easy to rear in captivity, their eggs have only rarely been observed in the field, making this an exciting moment for building knowledge of their mating system, and an informative one for the experiments we run in a lab setting. So after a quick happy snap, I return the clutch carefully, and energised, leave them to continue on their way.

On a final note, I have been both professionally and personally privileged to have the opportunity to work in the area surrounding Kati Thanda – Lake Eyre. I would like to acknowledge the traditional custodians of the Country here and their deep spiritual and cultural connection to this incredibly beautiful area. In particular, thank you to Reg Dodd of the Arabunna people for his patience in imparting to me a strong impression of the region and its environment. Thanks also to Jodie and Nathan at the Peake Station for their friendly reception and help in allowing us to access the station.